Image processing with anti-forgery provision

ABSTRACT

Disclosed is an image processing apparatus having a discrimination function for identifying a specific original (e.g., a banknote). The apparatus inputs pattern data which is obtained by reading a specific original, stores the inputted pattern data, synthesizes the stored pattern data with inputted original image data, and stores the result.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an image processing apparatus and, moreparticularly, to an image processing apparatus having a function ofadding a particular pattern to a reproduced image.

2. Description of the Related Arts

Copying machines capable of obtaining a multi-color copy having highimage quality have been recently developed. The recent improvements inthe picture quality of copying machines which now have a colorcapability have been accompanied by the fear of counterfeiting, in whichspecific originals such as bank notes and securities, which are notmeant to be copied, are duplicated at such a high picture quality thatthe copies are almost indistinguishable from the originals. However, inthe prior art, it was almost impossible to identify the copying machineused for counterfeiting or the user who misused the machine, from theduplicates.

In a case where an original which should not be copied has been copiedfor improper use, it is important to trace back to the copy user orabused copying machine.

To identify the copying machine used for copying, a method for adding aparticular pattern to duplicates is suggested by the present applicantin U.S. Pat. No. 5,257,119 and U.S. Ser. No. 858,500.

However, there is the drawback that, if the function for adding apattern is forged, the method cannot be fully functioned.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide animage processing apparatus which can eliminate the above-describeddrawback in the prior arts.

It is another object of the present invention to provide an imageprocessing apparatus capable of specifying the information on a copyingmachine used for copies, machine user, or a time copies are made inaccordance with duplicates, in a case where an original which should notbe copied is duplicated.

According to the present invention, the foregoing object is attained byproviding an image processing apparatus comprising: storage means forstoring pattern data inputted in accordance with a predetermined mode;and synthesizing means for synthesizing the pattern data stored in thestorage means with inputted original image data and outputting thesynthesized data.

It is another object of the present invention to provide an imageprocessing apparatus comprising: reading means for reading a specificimage and inputting pattern data; storage means for storing the patterndata inputted by the reading means; synthesizing means for synthesizingthe pattern data stored in the storage means and inputted original imagedata; and recording means for recording a result of synthesizing by thesynthesizing means.

It is another object of the present invention to provide an imageprocessing apparatus comprising: reading means for reading a specificimage and inputting image data; decoding means for decoding the imagedata which is inputted by the reading means; conversion means forconverting the inputted image data into pattern data in accordance witha result of decoding by the decoding means; storage means for storingthe pattern data converted by the conversion means; synthesizing meansfor synthesizing the pattern data stored in the storage means andinputted original image data; and recording means for recording a resultof synthesizing by the synthesizing means.

Other features and advantages of the present invention will be apparentfrom the following description taken in conjunction with theaccompanying drawings, in which like reference characters designate thesame or similar parts throughout the figures thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of the construction of an image scanner 201 inaccordance with a first embodiment of the present invention;

FIG. 2 is a sectional side view of the construction of a copying machinein accordance with the first embodiment of the present invention;

FIG. 3 is a block diagram of the construction of a determination circuit409 of the first embodiment;

FIG. 4 is a block diagram of the construction of a thinning-out circuitof the first embodiment;

FIG. 5 is a block diagram of the construction of a frequency dividingcircuit of the first embodiment;

FIG. 6 is a block diagram of the construction of an integrator 306 ofthe first embodiment;

FIG. 7 is a timing chart of a signal in the main scanning direction inaccordance with the first embodiment;

FIGS. 8 and 9 are diagrams of examples of input/output of the integrator306 of the first embodiment;

FIG. 10 is a block diagram of the construction of a comparator module308 of the first embodiment;

FIG. 11 is a block diagram of the construction of a pattern additioncircuit 410 of the first embodiment;

FIG. 12 is an example of the results of duplications in accordance withthe first embodiment;

FIG. 13 is a flowchart illustrating a procedure of setting a patternlevel selection signal PS in accordance with a CPU 414 of the firstembodiment;

FIG. 14 is a top view of the original table in accordance with the firstembodiment;

FIG. 15 is a flowchart illustrating a service mode in accordance withthe first embodiment;

FIG. 16 is a diagram illustrating a relationship between the signal CNOand the printing output in accordance with the first embodiment;

FIG. 17 is a block diagram of the construction of a pattern additioncircuit of the second embodiment;

FIG. 18 is an example of the results of duplications in accordance withthe second embodiment;

FIG. 19 is a diagram illustrating a pattern reading position inaccordance with the second embodiment;

FIG. 20 is an example of the results of duplications in accordance withthe third embodiment;

FIG. 21 is a diagram illustrating a pattern reading position inaccordance with the fourth embodiment;

FIG. 22 is a block diagram of the construction of a pattern additioncircuit 410 of the seventh embodiment;

FIG. 23 is a top view of the original table in accordance with theseventh embodiment;

FIG. 24 is a flowchart illustrating a pattern reading operation inaccordance with the seventh embodiment;

FIG. 25 is a diagram illustrating the bar code reading data of theseventh embodiment; and

FIG. 26 is the bar code of the seventh embodiment.

FIG. 27 is the operation section of the second embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will now be described indetail in accordance with the accompanying drawings.

Copying machines will be described as embodiments of the presentinvention, however, it goes without saying that this does not impose alimitation upon the present invention, for the present invention isapplicable also to any other kind of apparatus. In the presentinvention, the possible counterfeits includes bank notes, securities andoriginals of confidential documents.

<First Embodiment>

[General View of the Apparatus]

FIG. 2 is a sectional side view showing the construction of a copyingmachine in accordance with the first embodiment of the presentinvention. Numeral 201 denotes an image scanning section 201 which readsan original at a resolution of 400 dpi (dots/inch) and processes adigital signal. Numeral 202 denotes a printing section 202 which printsa full-color image corresponding to the original image read by the imagescanning section 201 on a print sheet at a resolution of 400 dpi.

The image scanning section 201 includes a pressure plate having a mirrorsurface 200. An original 204 on a glass table (platen) 203 is irradiatedby means of lamps 205, an image is formed on a three-line sensor(hereinafter referred to as a "CCD") 210 via mirrors 206, 207, and 208and a lens 209, and the image is sent to a signal processor 211 asfull-color information red (R), green (G) and blue (B) components. Theentire original is scanned (sub-scanning) by mechanically moving thecarriage 227 fixing the lamps 205 and mirror 206 at a velocity v as wellas the mirrors 207, 208 at a velocity 1/2 v in a in a directionperpendicular to the electrical scanning direction of the line sensor (amain scanning direction).

The signal processor 211 electrically processes the read image signal,separates the signal into magenta (M), cyan (C), yellow (Y), and black(BK) components and sends these components to the printing section 202.At least one component among the M, C, Y, BK components is sent to theprinting section 202 per scan of the original in the image scanningsection 201, and a single print-out is completed by a total of fourscans of the original.

Each image signal M, C, Y or BK received from the image scanning section201 is sent to a laser driver 212. The laser driver 212 modulates anddrives a semiconductor laser 213 in accordance with the received imagesignal. The laser light is made to scan across a photosensitive drum 217via a polygonal mirror 214, an f-θ lens 215 and a mirror 216. Numeral218 represents a revolving developer comprising a magenta developingsection 219, a cyan developing section 220, a yellow developing section221 and a black developing section 222. These four developing sectionscome into alternate contact with the photosensitive drum 217 so that anelectrostatic image formed on the photosensitive drum is developed bymeans of toners. Numeral 223 represents a transfer drum upon which paperfed from a paper cassette 224 or 225 is wound so that the imagedeveloped on the photosensitive drum 217 may be transferred to thepaper.

After four colors M, C, Y and BK have thus been transferredsuccessively, the paper is ejected through a fixing unit 226.

[Image Scanner Unit]

FIG. 1 is a block diagram of the construction of the image scanningsection 201 according to the first embodiment. Numerals 210-1, 210-2,and 210-3 denote CCD line sensors (solid image pick-up elements) havingspectroscopic sensitivity characteristics such as to be sensitive to red(R), green (G) and blue (B), respectively. After the A/D conversion, aneight-bit signal having a value of 0 to 255 is outputted.

Since the CCD line sensors 210-1, 210-2, and 210-3 used in the firstembodiment are placed at regular intervals, relative spatial deviationsthereof are corrected by delay elements 401 and 402.

Numeral 403, 404, and 405 denote logarithmic converters (log converters)comprising look-up table ROMs or RAMs which convert a luminance signalinto a density signal. Numeral 406 denotes a masking/UCR (under colorremoval) circuit. The detail description is omitted here since this typeof circuit is well known. Generally, when each of the signals of M, C, Yand BK for output is read according to three input signals, the signalis outputted as a signal having a predetermined bit length, namely 8bits, in a frame-sequential order.

Numeral 407 denotes a spatial filter circuit which corrects thecharacteristics of spatial frequencies of an output signal (MTF).Numeral 408 denotes a density conversion circuit which corrects densitycharacteristics of the printing section 202. The density conversioncircuit 408 comprises ROMs or RAMs which are similar to those of the logconverters 403 to 405.

Numeral 414 denotes a microcomputer (hereinafter referred to as a "CPU")for controlling the present apparatus. Numeral 415 denotes a ROM storinga program which operates the CPU 414. Numeral 416 represents a RAM whichis used as a work area for executing various programs. Numeral 413represents an input/output port (hereinafter referred to as an "I/Oport") connected to the CPU 414. Numeral 409 represents a determinationcircuit which discriminates a specific original.

The determination circuit 409 discriminates a possibility that theoriginal placed on the original table is at least one of plurality ofspecific originals. The determination signal H is outputted in two bits.If there is a strong possibility that the original is one of thespecific originals, H="3" is outputted. On the other hand, if thepossibility is rare, H="0" is outputted. The determination circuit 409further comprises a thinning-out circuit 301 which performs athinning-out processing of the inputted signals R, G, B and a frequencydividing circuit 310, which are described later with reference to FIG.3.

A signal CNO is a two-bit frame-sequential signal which is a controlsignal indicating the order of the four reading operations (scanningoperations) with respect to four output colors M, C, Y, and BK for eachcolor image. FIG. 16 shows the relation between the signal CNO and theprinting output according to the first embodiment. The signal CNO isgenerated by the CPU 414 through the I/O port 413 to change conditionsfor the operation of the masking UCR circuit 406. The signal CNO is alsoinputted to the determination circuit 409 to change the determinationcriteria with respect to the four reading operations and thusdiscrimination on a different specific original can be performed.

Numeral 410 denotes a pattern addition circuit at which a pattern whichcannot easily be discriminated with human eyes is added to a duplicateimage corresponding to a two-bit pattern level selection signal PSdesignated by the CPU 414. The pattern to be added is generated from theimage signal P read by the reader.

[Timing Chart]

FIG. 4 is a block diagram of the construction of the frequency dividingcircuit 310 in accordance with the first embodiment. FIG. 5 is a blockdiagram of the construction of the frequency dividing circuit 310 inaccordance with the first embodiment. FIG. 7 is a timing chart ofvarious signals with respect to the main scanning direction inaccordance with the first embodiment.

A signal VSYNC is a sub-scanning period signal which indicates an imageoutput period of sub scanning. A signal HSYNC is a main scanningsynchronizing signal for synchronizing the start of the main scanning.CLK represents an image transfer clock which is a master clock forvarious image processings in the first embodiment.

On the other hand, CLK' represents a clock which is obtained by dividingthe frequency of the CLK by 4 to be used as a master clock for thedetermination circuit 409. A signal SEL is a timing signal for use inthe thinning-out circuit 301. The clock CLK' and signal SEL aregenerated by the frequency dividing circuit 310 shown in FIG. 5.

The thinning-out circuit 301 and the frequency dividing circuit 310 willnow be described below.

In FIG. 4, numerals 455 to 457, and 461 to 466 represent flip flops andnumerals 458 to 460 represent selectors. In FIG. 5, numerals 451 and 453represent inverters, numeral 452 represents a two-bit counter, andnumeral 454 represents an AND gate.

The flip flops 455, 456, 457, 461, 462, 463 and the selectors 458, 459460 hold data at the timing of the clock CLK while the flip flops 464,465, and 466 hold data at the timing of the clock CLK'.

In the frequency dividing circuit 310, the two-bit counter 452 iscleared (initialized) by the signal HSYNC which is the main scanningsynchronizing signal, counts the CLK thereafter, and outputs the countvalue in two bit (D0, D1). The upper bit D1 of these count values isoutputted as CLK', and a logical product of an inverted signal of thelower bit DO and the upper bit D1 is outputted as a signal SEL.

Consequently, in the thinning-out circuit 301, the signal R (G, or B)transferred at CLK is thinned out at a rate of 1/4 and is synchronizedwith CLK' to obtain a signal R' (G', or B') as shown in FIG. 7.

[Discrimination Circuit]

FIG. 3 is a block diagram of the construction of the determinationcircuit 409 in accordance with the first embodiment. The thinning-outcircuit 301 shown in FIG. 4 thins out data to reduce the load on theprocessing circuit of the determination circuit 409. Numeral 302represents a color-matching look-up table RAM (hereinafter referred toas a "LUT") which performs color matching between each of a plurality ofspecific originals (securities, bank notes, etc.) and inputted data. TheLUT 302 investigates color distribution with regard to 32 specificoriginals in advance and holds the results of judgment such as the bitinformation when the color of a pertinent pixel coincides with a colorof the specific original and when the color does not coincide with thecolor of the specific original. The number 32 as the total of specificoriginals applies in the case where the judgment of eight types ofspecific originals are respectively assigned to four scanning operationsfor M, C, Y, and BK.

In the LUT 302, the signal CNO, which is a frame-sequential signal, isinputted to the two higher order address bits, and five higher orderbits of the thinned-out image signal of each of the colors R, G, B areinputted to the 15 lower order address bits. In each of the signal CNOvalues 0 to 3, whether the color tone of the pertinent pixel coincideswith the color tone of the 8 specific originals is simultaneouslyoutputted in correspondence with the 8-bit data. Accordingly,determination is made with respect to the 32 specific originals by fourcycles of read scanning.

Numerals 303-1, 303-2, . . . , 303-8 shown in FIG. 3 represent a colortone determination circuit constituted of the same hardware. Eachcircuit comprises an integrator 306, registers 307 and a comparatormodule 308, determines a possibility of the existence of a specificoriginal in the read originals, and outputs a 2-bit determinationresult. Numeral 309 represents a maximum value circuit which outputs amaximum value among the determination results outputted from the colortone determination circuits 303-1, 303-2, . . . , 303-8. That is, thedetermination result corresponding to one of the 8 specific originalswhich is the most probable to exist is outputted.

[Integrator]

FIG. 6 is a block diagram of the construction of the integrator 306 inaccordance with the first embodiment, FIG. 8 is a diagram of an exampleof an output from the integrator 306, and FIG. 9 is a diagram of anexample of am input to the integrator 306.

Numerals 501 and 505 shown in FIG. 5 represent flip flops which holddata at the timing of the leading edge of a clock signal CLK'. Numeral502 represents a multiplier to which two eight-bit signals (A, B) areinputted. The multiplier 502 multiplies these signals and outputs aneight-bit signal (A×B/255) as the result. Numeral 503 represents amultiplier to which a one-bit input signal (A) and an eight-bit inputsignal (B) applied. The multiplier 503 multiplies these signals andoutputs an eight-bit output signal (A×B) as the result. Numeral 504represents an adder to which two eight-bit input signals (A, B) areinputted. The adder 504 adds these signals and outputs an eight-bitsignal (A+B) as the result.

Consequently, in the operation of the integrator 306, an 8-bit outputsignal yi with respect to a binary input signal xi is expressed by thefollowing equation when a binary input signal xi is applied:

    yi=(α/255)·y.sub.i-1 +β·x.sub.i-1 (1)

where values α and β in this equation are predetermined constants. Thevarious characteristics of the integrator 306 are determined by thesevalues.

For example, when α=247 and β=8, an output yi of the kind shown in FIG.9 is outputted in response to an input xi of the kind shown in FIG. 8.

An input which is "1" despite the fact that almost all values peripheralthereto are "0", as in the manner of points 701, 702, is considered tobe noise. Similarly, an input which is "0" despite the fact that almostall values peripheral thereto are "1", as in the manner of point 703, isconsidered to be noise. This is processed by the integrator 306, anappropriate threshold value such as values 704-1 (R1), 704-2 (R2), and704-3 (R3) in the registers 307 shown in FIG. 3 is set, and the outputyi of the integrator 306 is binarized based upon this threshold value,thereby making it possible to eliminate the noise.

[Comparator Module]

FIG. 10 is a block diagram of the construction of the comparator module308 according to the first embodiment. In FIG. 10, numerals 801, 802,and 803 represent comparators, numeral 804 represents an inverter,numeral 805 represents an AND gate, and numerals 806 and 807 representOR gates. Threshold values R1, R2, and R3 mentioned above with referenceto FIG. 3 are previously set in the registers 307-1, 307-2, and 307-3,respectively. The relation such as R1>R2>R3 is established. Accordingly,the determination result is quantized into 2 bits and output ted. Thatis:

OUTPUT=11 (binary) is outputted if R1<(input),

OUTPUT=10 (binary) is outputted if R2<(input)≦R1,

OUTPUT=01 (binary) is outputted if R3<(input)≦R2, and

OUTPUT=00 (binary) is outputted if (input)<R3.

[Pattern Addition Circuit]

FIG. 11 is a block diagram of the construction of the pattern additioncircuit 410 according to the first embodiment. FIG. 14 is a top view ofthe original table according to the first embodiment. In FIG. 11,numeral 901 represents a sub scanning counter, numeral 902 represents amain scanning counter, numeral 903 represents a look-up table RAM(hereinafter referred to as a "LUT"), numeral 905 represents a flipflop, numeral 913 represents an AND gate, numerals 906, 907, 908, and909 represent registers, numeral 910 represents a 4 to 1 selector,numerals 911 and 913 represent AND gates, numeral 912 represents anadder, and numeral 914 represents a binarization circuit which binarizesan image signal P which has gone through a spatial filter. Thebinarization circuit 914 outputs "1" when a value of the image signal isgreater than the predetermined threshold, while the circuit 914 outputs"0" when the value is smaller than the predetermined threshold. Thebinary data which is outputted from the circuit 914 is written in a dualport RAM 915. The image to be written in the dual port RAM 915 is animage which has been written in a particular place in the image scannerunit 201 such as 1201 in FIG. 14. The image is placed on a component inthe reader which cannot easily be exchanged, i.e. at the outer side ofthe original glass table (platen) 203 (a frame part supporting the glassplate) and the under surface of the supporting frame within the areawhere the image sensors of the carriage 226 can read that image.

When an image is written in the dual port RAM 915, the signal CNO is setto "0" (magenta recording scanning). The apparatus is controlled so thatthe image signal P is a signal made from the green (G) signal of the CCD210. This is because the green signal is the closest to the luminancesignal of the image among the signals which can be easily produced.

The content stored in the dual port RAM 915 is read via a data bus Dataand an address bus Adr by CPU 414. Since RAM 903 is also a dual port RAM(hereinafter referred to as a "RAM"), the CPU 414 writes into the RAM903 the same data as the one read out from the RAM 915. The operationsmentioned above are described below.

FIG. 15 is a flowchart illustrating a service mode according to thefirst embodiment in FIG. 15.

In the service mode, the CPU 414 sets the signal CNO to "0" (step S1501)and starts a pattern reading operation (step S1502). The CPU 414 sets aCPU address to the address of the dual port RAM 915 (step S1503) andreads the data of the dual port RAM 915 (step S1504).

The CPU 414 then sets the CPU address to the address of RAM 903 (stepS1505) and writes the data read out from the dual port RAM 915 withrespect to the RAM 903 (step S1506).

In this embodiment, it is arranged that a pattern to be added withrespect to the specific original is read once at the mode only a copymaintenance engineer can have access to it when the copying machine isinstalled.

The sub-scanning counter 901 counts the main scanning synchronizingsignal HSYNC while the main scanning counter 902 counts the pixelsynchronizing signal CLK. Each counter repeatedly counts the signal in acycle of a 9-bit width, that is, 512 cycles. As described above, the RAM903 stores the patterns to be added and is supplied with lower 6 bits ofeach count value from the sub scanning counter 901 and the main scanningcounter 902.

The AND gate 904 takes the logical product (AND) between the output ofthe RAM 903 and each bit of an upper 3-bit of the main scanning counter901 and the sub-scanning counter 902. This logical product issynchronized with CLK by the flip flop 905. After the AND gate 913 takesthe logical product between the 2-bit signals CNO "0" and "1", theresult of the AND operation is outputted to the AND gate 911. Thissignal supplied to the AND gate 911 is effective only when CNO=2, thatis, only when printing is being performed in yellow.

Values P1, P2, P3, and P4 are stored in advance in the registers 906,907, 908, and 909. One of the values P1, P2, P3, and P4 is selectedaccording to the pattern level selection signal PS designated by the CPU414. The value is supplied through the AND gate 911 to the adder 912where a pattern signal is added to an input signal V. The signalobtained by the adder 912 is outputted as a signal V'. Accordingly, whenCNO=2, that is, printing in yellow is being performed, the patternstored in the RAM 903 is repeatedly read out and added to the signal tobe outputted.

In a pattern addition mode, a relationship P1<P2 <P3<P4 is establishedin P1, P2, P3 and P4. In the selector 910, the following relation isset:

Y=A is set when s=00 (binary),

Y=B is set when s=01 (binary),

Y=C is set when s=10 (binary), and

Y=D is set when s=11 (binary).

Therefore, a pattern is added so that:

V'=V+P1 when PS=00 (binary),

V'=V+P2 when PS=01 (binary),

V'=V+P3 when PS=10 (binary), and

V'=V+P4 when PS=11 (binary).

The added pattern is formed with yellow toner alone so as to bedifficult to discriminate with human eyes. This method is intended toutilize the fact that the discriminating ability of human eyes is weakwith respect to a pattern formed only with yellow toner. Furthermore, itis arranged is such that the level of the pattern to be added can bevariable according to the possibility of the existence of a specificoriginal in the inputted original. It is thereby possible to make thepattern very difficult to discriminate in ordinary copies with humaneyes. On the other hand, the pattern is added more distinctly if thepossibility of the existence of a specific original is increased.

[Result of Duplication]

FIG. 12 is a diagram showing an example of the result of duplicationsaccording to the first embodiment. In FIG. 12, an added pattern isindicated by numeral 1001. The content stored in the ROM 903 is added.In the example shown in FIG. 12, the added pattern which is "ABCD" and"1234" in the two rows is formed in 64×64 pixels such as to be difficultto discriminate with human eyes. This patten is repeatedly formed atintervals of 512 pixels in the main scanning direction and at intervalsof 512 lines in the sub-scanning direction. As this added pattern, amanufacturer's serial number exclusively assigned to the copying machineor encoded pattern of this number can be formed to identify the machineused for copying a specific original by examining the duplicates.

If the possibility that a specific original which should not be copiedmay exist in the read image is strong, a more distinguishable patterncan be added.

In the first embodiment, the pattern adding pitch is predetermined as512 pixels in the main scanning direction, (or 512 line). The patternsare therefore added at intervals of approximately 32.5 mm since thecopying machine according to the first embodiment has a resolution of400 dpi (dots/inch). A bank note of the Bank of Japan has a width ofapproximately 76 mm in the direction along its short side. The shortside of the paper currencies of major countries in the world ranges fromapproximately 60 mm to 120 mm. The pattern can therefore be always addedon the duplicate of any bank note. Even if a part of a bank noteduplicate is cut out and abused, the information on the model number ofused copying machine can be specified by examining the duplicate andreading the added pattern.

[Flowchart]

FIG. 13 is a flowchart of the procedure of setting the pattern levelselection signal PS according to the first embodiment. Processing iscontrolled by the CPU 414.

Immediately after the start of copying, at step S1102, "0" is set in thepattern level selection signal PS. At Step S1103, the presentdetermination level H and the value of PS are compared. If the level His higher, the value of H is set in PS at step S1104. If the level H isnot higher, the process returns to step S1103. That is, the maximumvalue among the values from the copying start to the present time is setaccording to the recording history of the discrimination signal H.

As described above, in the first embodiment, a particular pattern whichis difficult to discriminate with human eyes is added in accordance withthe method of identifying a copying machine, so that the pattern can beused as a key to identifying the copying machine in a case where aspecific original (e.g. bank notes) which should not be copied isduplicated. The particular pattern is repeatedly added at a pitchshorter than the width of a bank note in the direction along the shortside thereof, so that the added particular pattern can always beincluded even in a part of a copy of the bank note which is cut out tobe abused. It is possible to ascertain the copying machine used or theperson who has operated the copying machine or to narrow down suspectedmachines or persons by examining the added pattern.

<The Second Embodiment>

In the first embodiment, the added patterns indicating characters ornumbers are utilized, however, in the second embodiment, a bar code isutilized as an added pattern in order to foil counterfeiters. The wholeconstruction is similar to that of the first embodiment. However, thecharacteristic of the second embodiment is the pattern addition circuitin particular. Accordingly, the description for the functions which arecommon both in the first and second embodiment is omitted here and thepattern addition circuit is mainly described.

(Pattern Addition Circuit)

FIG. 17 is a block diagram illustrating the construction of the patternaddition circuit according to the second embodiment. FIG. 19 is adiagram illustrating a reading position of a adding pattern according tothe second embodiment.

This embodiment (FIG. 17) differs from that of the first embodiment(FIG. 11) in that the count value in the main scanning direction isinputted to the dual port RAM 917. The count values are generated by themain scanning counter 916. The main scanning counter 916 is a counterwhich picks up only the pixel data of a particular main scanningaddress. The dual port RAM 917 writes the data received from thebinarization circuit 914 only when the particular main scanning addressis counted. The above-mentioned particular main scanning address is aposition for the bar codes 2201, 2202 which are stored in a particularpart in the image scanner 201. The component which is storing the barcodes is a component of the image scanner 201 which cannot easily beexchanged, that is, the outer side of the original glass table 203 (theframe part supporting a glass plate) and the under surface of thesupporting frame within the area where the image sensor of the carriage226 can read that image.

(Results of Duplication)

FIG. 18 is a diagram illustrating an example of the results ofduplications according to the second embodiment.

In the second embodiment, the code of the bar code 2201 is encoded by anencoding function and the encoded code is further converted to the barcode 2202.

The bar code 2201 is the result when the manufacture's serial number ofthe image scanner 201 is coded. As an instance shown in FIG. 18, the barcode, the pattern "1234", is added in 64×64 pixels so that it isdifficult to distinct with human eyes. The patterns are repeatedlyplaced at the intervals of 512 pixels in the main scanning direction and512 lines in the sub scanning direction. Since the content of the dualport RAM 917 according to the second embodiment represents the densitychanges of the pixels in the sub-scanning direction of the scanningsystem, the bar code can be easily decoded by reading the contentthrough the data bus Data and address bus Adr.

Similarly, the code "1234" is written in the RAM 903 as image data. Thecode "1234" is a code that the bar code 2201 is decoded by the data busData and address bus Adr. Since this operation is similar to that of theabove-described service mode in FIG. 15 without having a step ofdecoding a pattern on the basis of image data read-out from RAM 917, thedescription for the operation is omitted.

The pattern forgery detection method is now described.

As a pattern forgery detection method, log _(e) (x) is used as anencoding function and exp (x) is used as a decoding function. Take anexample of the case where the code content of the bar code 2201 is"1234". When X=1234, log _(e) (1234)=7.118. The bar code 2202 isobtained when 7.118 is converted to a bar code. In the contrast withthis, when the bar code 2202 is read, exp (7.118)=1234.

Accordingly, a mutual relation is examined and if it is not correct, itis determined that the bar code is forged. The copy operation is thensuspended, and the display 2702 of the operation section 2701 of themain apparatus indicates to call a copy maintenance engineer (FIG. 27).The capability for preventing counterfeits is thus improved. Theabove-described pattern forgery detecting processing can be programmedas a pattern forgery detection mode, so that the determination isperformed before the original is read when the copying start key ispressed by a user.

It should be noted that only the difference between the secondembodiment and the first embodiment is described above and otherfunctions in the second embodiment are the same as those of the firstembodiment.

Accordingly, in addition to the effects of the first embodiment, thesecond embodiment makes it possible to prevent the printing of aspecific image by detecting an existence of the pattern forgery.

<Third Embodiment>

In the second embodiment, the content in which the bar code is decodedis added to an output image. However, this does not impose a limitationupon the present invention, for it can be arranged that the image of thebar code can be added to the output image as an added pattern.

In the third embodiment, the method for adding a pattern is improved inthe same construction as that of the second embodiment.

FIG. 20 is a diagram illustrating an example of the result ofduplication according to the third embodiment. In FIG. 20, numeral 1003denotes a bar code pattern indicating either the bar code 2201 or 2202in FIG. 19 as it is. The method for adding this bar code pattern 1003 issimilar to that of the first embodiment.

Accordingly, on the output image to which the bar code pattern is added,the information, namely a manufacture's apparatus serial number, can beidentified in a manner such that the output image is read and the addedbar code is decoded. In the third embodiment, thus, the function as abar code pattern decoding mode can be obtained.

<The Fourth Embodiment>

In the second embodiment, for the pattern forgery detecting mode, thetwo bar codes 2201 and 2202 are added to the image scanner unit,however, the present invention is not limited to this embodiment. It canbe arranged so that only the bar code in which the encoded code contentis converted to a bar code is added to the image scanner unit. Since theoverall construction of the fourth embodiment is similar to that of thesecond embodiment, the detail description is omitted here and the onlycharacteristic part in the fourth embodiment is described.

FIG. 21 is a diagram illustrating a reading pattern position of theadded pattern according to the fourth embodiment.

As similar to the second embodiment, the particular main scanningaddress is a position for the bar codes 3202 which is stored in aparticular part in the image scanner 3201. The component which storesthe bar codes is a component of the image scanner 3201 which cannoteasily be exchanged, that is, as shown in FIG. 21, the outer side of theoriginal glass table 3203 (the frame part supporting a glass plate) andthe under surface of the supporting frame within the area where theimage sensors of the carriage 3226 can read that image.

In the fourth embodiment, the code content "1234" which is a codecontent before the decoding, taken an example in the second embodiment,is stored in the backup RAM in the control circuit and inputted from theoperation section at a shipment from the factory. If the mutual relationbetween the code content stored in the backup RAM and the content of thedecoded bar code 2202 is not correct, it is determined that the bar code2202 is forged or the content of the backup RAM is rewritten. From thisjudgment, the main apparatus suspends the copying operation and theoperation section displays the indication to call a copy maintenanceengineer.

In this way, the same effect as that of the second embodiment can beobtained.

<The Fifth Embodiment>

In each embodiment, the manufacturer's serial number of a copyingmachine or an encoded pattern of this number is used as a particularpattern to be added. However, any other pattern can be added as long asit has information which serves for identification of the copyingmachine.

For example, the information can be such as the machine manufacturingdate, the machine lot number, and/or a machine version name foridentifying the machine.

<The Sixth Embodiment>

In each embodiment, the image which is written in the particular placewhere the image scanner can read that image is read as a pattern to beadded. It can be arranged that the original of the code indicating theuser, the code capable of identifying the user, is placed on theoriginal glass table and read it in advance at the machine installation.

<The Seventh Embodiment>

FIG. 22 illustrates a block diagram of the pattern addition circuit 410according to the seventh embodiment. Numeral 901 is a sub-scanningcounter, numeral 902 is a main scanning counter, numeral 903 is alook-up table RAM, numeral 905 is a flip flop, numeral 913 is an ANDgate, numerals 906, 907, 908, 909 are registers, numeral 910 is a 4 to 1selector, numerals 911, 913 are AND gates, and numeral 912 is an adder.

The data of the image signal P which has gone through the spatial filteris written in the dual port RAM 915.

For the data to be written in the RAM 915, only the pixel data of thespecific sub-scanning address is needed. Therefore, the sub-scanningcounter 931 counts that specific address and the data for one scanningline is written in RAM 915 at the pertinent address. This is because theimage information for writing in RAM 915 is a bar code which is writtenat the particular place of the reader in the main scanning direction asshown 4201 in FIG. 23.

The sub-scanning counter 931 counts the main scanning synchronizingsignal HSYNC and outputs a signal CU when the value of the resister setin the CPU becomes equal to the count value. The address generationcircuit 932 which received the signal CU generates an address value forone line and supplies to the RAM 915. The signal CU is inputted to thelight enable signal of the RAM 915 and the image data at the particularsub scanning position set by the CPU can be written in the RAM 915.

When an image is written in the RAM 915, the signal CNO is set to as "0"(scanning for magenta). That is, the image signal P is a signal (thedensity signal of magenta) made from the green (G) signal of the CCD210. This is because the green signal is the closest to the luminancesignal of the image among the signals which can be easily produced.

The bar code 4201 is the coded manufacture's serial number of the readerand represents "1234" in FIG. 23. Since the content of the dual port RAM915 represents the density change of the pixels in the main scanningdirection of the scanning system, the bar code can be easily decoded byreading the content from the CPU through the data bus Data and addressbus Adr.

In this case, reading accuracy can be improved by reading the content ata different scanning position for a plurality of times. To do so, it canbe arranged that the count value of the register of the sub-scanningcounter 931 is reset by the CPU and the same operation is performed. Ifthe content is read three times and the results are "1234", "1234", and37 1244", it is determined that the correct result is "1234".

A bar code comprises vertical black bars and rectangular white areasbetween two bars (hereinafter referred to as "white bars". These barshave two kinds of width in short side: approximately 0.5 mm and 1 mm.When these bars are read at 400 dpi, the number of pixels for 0.5 mm isapproximately 8 pixels and the number of pixels for 1 mm isapproximately 16 pixels. The difference of these widths can be easilydistinct.

FIG. 25 illustrates the image data at which the bar code is read, thatis, the image data written in the RAM 915. As the the density is higher,the area is darker and the data is closer to the value 255, while asdensity is lower, the area is whiter and the data is closer to the value0.

It is determined that the area at which the density is higher than 127is black, a black bar, while the area at which the density is lower than126 is white, a blank bar. If the width of a bar is less than 12 pixels,it is a bar having the width of 0.5 mm (a narrow bar), while the widthis over 12 pixels, it is a bar having the width of 1 mm (a wide bar).

FIG. 25 is the data when the bar code of FIG. 26 is read according tothe above-described criteria. As shown in FIG. 25 , the black bar isread as 0100101 and the white bar is as 000100. However, it is assumedthat the narrow bar is "0" and the wide bar is "1". The first "0" of theblack bar is a start bit. Each three bits of the black bars is readafter that, 100 corresponds to "2" and 101 corresponds to "4".Similarly, when the white bars are read, 000 is "1", 100 is "3" and itturns out to be "1234" as a whole. FIG. 13 is a flowchart illustratingthis operation. The pattern reading is operated when the main switch isturned on.

Since RAM 903 is a dual port RAM (hereinafter referred to as a "RAM"),the code "1234" is written in the RAM 903 as image data. The code "1234"is a code that the bar code 1201 is decoded by the data bus Data andaddress bus Adr. FIG. 24 is a flowchart illustrating this operation. Thepattern is read when the main switch is turned on.

The sub-scanning counter 901 counts the main scanning synchronizingsignal HSYNC while the main scanning counter 902 counts the pixelsynchronizing signal CLK. Each counter repeatedly counts the signal in acycle of a 9-bit width, that is, 512 cycles. As described above, the RAM903 stores the patterns to be added and is supplied with lower 6 bits ofeach count value from the sub-canning counter 901 and the main scanningcounter 902.

The AND gate 904 takes the logical product (AND) between the output ofthe RAM 903 and each bit of an upper 3-bit of the main scanning counter901 and the sub scanning counter 902. This logical product issynchronized with CLK by the flip flop 905. After the AND gate 913 takesthe logical product between the 2-bit frame-sequential signals CNO "0"and "1", the result of the AND operation is outputted to the AND gate911. This signal supplied to the AND gate 911 is effective only whenCNO=2, that is, only when printing is being performed in yellow.

Values P1, P2, P3, and P4 are stored in advance in the registers 906,907, 908, and 909. One of the values P1, P2, P3, and P4 is selectedaccording to the pattern level selection signal PS designated by the CPU414. The value is supplied through the AND gate 911 to the adder 912where a pattern signal is added to an input signal V. The signalobtained by the adder 912 is outputted as a signal V'. Accordingly, whenCNO=2, that is, printing in yellow is being performed, the patternstored in the RAM 903 is repeatedly read out and added to the signal tobe outputted.

FIG. 24 is a flowchart illustrating the pattern reading operation in theseventh embodiment.

This embodiment differs from the embodiment of FIG. 15 in that theabove-described operation is performed not at the service mode, butwhenever the main scanning switch is turned on and there is the stepS1510 where the pattern is decoded based on the image data read from theRAM 915.

<The Eighth Embodiment>

In the above-described seventh embodiment, the narrow bar and wide barin a bar code are discriminated by a single threshold (12 pixels).However, it can be arranged that, in the case where there is a bar inwhich the width is out of the predetermined range, it is determined thatthere is a strong possibility that the bar code is forged. Accordingly,the whole operation of the apparatus is suspended and the operationsection can display the indication to call a copy maintenance engineer.

More particularly, it is predetermined that the width of a narrow bar isin the range of 5 to 11 pixels and that of a wide bar is in the range of13 to 19 pixels. If there is a bar in which the width is out of thepredetermined ranges, it is determined that there is a strongpossibility that the bar code has been forged and the whole operation ofthe apparatus is suspended.

<The Ninth Embodiment>

In the above-described seventh embodiment, the discrimination between ablack bar and white bar in a bar code is performed by the thresholdvalue (127) of density. However, it can be arranged that, in the casewhere there is the value of density which is in out of a predeterminedrange, it is determined that there is a strong possibility that the barcode has been forged and the whole operation of the apparatus issuspended.

More particularly, it is predetermined that the density of a white baris in the range of values 0 to 50 and that of a black bar is in therange of values 200 to 255. If there is a bar in which the density valueis out of the predetermined ranges, it is determined that there is astrong possibility that the bar code has been forged and the wholeoperation of the apparatus is suspended.

<The Tenth Embodiment>

In the seventh embodiment, the discrimination between the black bar andwhite bar is performed on the density of green by a single thresholdvalue (127). However, it can be arranged that the discrimination isperformed on all color component signals, that is, the three colors ofred, blue, green. In the case where the bar code having the value ofdensity which is not in the predetermined ranges, it is judged thatthere is a strong possibility that the bar code has been forged.Accordingly, all operations of the apparatus are suspended and thedirection to call a copy maintenance engineer can be displayed on theoperation section.

More particularly, since a bar code is normally printed in black on awhite ground, in each of the density signals of magenta, yellow, cyanwhich are made based on red, green, blue, it can be predetermined thatthe density from 0 to 50 is a white bar and from 200 to 255 is a blackbar. If there is a bar in which the density is out of the predeterminedranges, it is determined that there is a strong possibility that the barcode has been forged and the whole operation of the apparatus issuspended.

The operation for reading a bar code by the 3-color density signals canbe performed when the operation that the signal CNO is set to as "0" andthe operation that the image of the bar code is written in the RAM 915in the seventh embodiment is similarly performed for the signal CNO=1and the signal CNO=2.

<The Eleventh Embodiment>

In the above-described seventh embodiment, in the case where a bar codeis read and the pattern which is not a predetermined pattern exists, itis judged that there is a strong possibility that the bar code has beenforged. Accordingly, all operations of the apparatus are suspended andthe direction to call a copy maintenance engineer can be displayed onthe operation section.

<The Twelfth Embodiment>

In the seventh embodiment, the pattern is read when the main switch isturned on. However, it can be arranged that the pattern is read everytime copying is designated.

In each of the embodiments described above, a laser-beam printer istaken as an example of the printing apparatus. However, this does notimpose a limitation upon the invention, for the invention is applicablealso to an ink-jet printer and a thermosensitive printer. In particular,the invention is applicable to a so-called bubble-jet printer employinga head of the type which jets droplets by utilizing film boiling thatrelies upon thermal energy.

In each of the foregoing embodiments, the patterns are added in yellow.However, this does not impose a limitation upon the invention, for thecolor can be replaced by a neutral tint such as yellow green or grey ora bight color such as light purple or light green.

Furthermore, in each of the foregoing embodiments, the image of anoriginal is inputted by the scanning section. However, this does notimpose a limitation upon the invention, for it is permissible to inputan image entered by a still-video camera or ordinary video camera, aswell as an image produced by computer graphics.

It goes without saying that the present invention includes a case wheremore than two of the embodiments described above are combined.

The present invention is not limited to the above-descried embodimentsbut can be modified in various ways within the scope of the claims.

It should be noted that the present invention may be applied to a systemcomposed of a plurality of devices or to an apparatus comprising onedevice. It goes without saying that the present invention can be appliedalso to a case where the above-mentioned effects are attained bysupplying a program to a system or apparatus.

What is claimed is:
 1. An image processing apparatus comprising:imagereading means for reading an original, and for generating image data; amember, which holds predetermined information, placed in the apparatusin a position to be read by said image reading means; and addition meansfor adding a predetermined pattern based on the predeterminedinformation to an image represented by the image data generated by saidimage reading means, wherein the predetermined information correspondsto identification information unique to an individual apparatus.
 2. Theapparatus according to claim 1, wherein said image reading meansincludes a linear sensor for generating the image data.
 3. The apparatusaccording to claim 1, wherein said member represents a bar code.
 4. Theapparatus according to claim 1, wherein said member is placed in analmost undetachable position of the apparatus.
 5. The apparatusaccording to claim 1, wherein the identification information is amanufacturer's serial number.
 6. The apparatus according to claim 1,wherein said addition means repeatedly adds the pattern at apredetermined interval.
 7. An image processing apparatuscomprising:image reading means for reading an original, and forgenerating image data; a member, which holds identification informationcorresponding to said apparatus, placed in said apparatus at a positionto be read by said image reading means; and control means forcontrolling the apparatus in accordance with the identificationinformation read from said member, wherein the identificationinformation is unique to an individual apparatus.
 8. The apparatusaccording to claim 7, wherein said image reading means includes a linearsensor for generating the image data.
 9. The apparatus according toclaim 8, wherein said member is represents a bar code arranged in thesame direction as the sensing direction in the linear sensor.
 10. Theapparatus according to claim 8, wherein said member is represents a barcode arranged in a direction perpendicular to the sensing direction inthe linear sensor.
 11. The apparatus according to claim 7, wherein saidmember is placed in an almost undetachable position of the apparatus.